biden. >> reporter: on a surprise visit to afghanistan, president obama said that the timing of his trip was no accident. >> one year ago, from a base here in afghanistan, our troops launched the operation that killed osama bin laden. >> reporter: now, for the first time, new details of bin laden's last does are being made public and newly declassified letters found in his compound. in a report reclosed thursday from the combatting terrorism center at west point, bin laden appears concerned al-qaeda attacks had killed too many muslims and damaged his support. in 2010, bin laden wrote, quote, i plan to release a statement that we are starting a new phase to correct the mistakes we made. in doing so, we shall reclaim, god willing, the lost trust of a large segment of those who lost their trust in the gee hood. experts say the letters show a frustrated bin laden who was hiding. >> this guy spent most of his time hovering some place trying not to be killed. he did not have much operational control of the organization although he maintained check the with it. >> reporter: one other thing